docs: switch architecture to PNG embed (HF model cards render PNG reliably); tighten prose

README.md

@@ -77,11 +77,11 @@ The cascade architecture (A gate + B specialist) is the result of **421 autonomo
 
 ## Architecture
 
-![ClinicalMem BitNet b1.58 — A+B cascade architecture](architecture.svg)
+<p align="center">
+  <img src="architecture.png" alt="ClinicalMem BitNet b1.58 — A+B cascade architecture" width="900">
+</p>
 
-> *Source diagram (Mermaid): [`architecture.mmd`](architecture.mmd). Rendered to SVG with `@mermaid-js/mermaid-cli` v11.x and committed alongside the model so the architecture renders correctly on every viewer (HF model cards, GitHub, GitLab, NPM, etc.) without depending on a Mermaid runtime.*
-
-> **Source**: BitNet b1.58 architecture from Ma, Wang, Ma, et al. ([arXiv:2402.17764](https://arxiv.org/abs/2402.17764)). This is a clean-room Python implementation with **pure-integer Q16.16 fixed-point arithmetic** — no `torch` runtime dep, no GPU required. Training used PyTorch + Straight-Through Estimator on H200 SXM (RunPod).
+Architecture from Ma, Wang, Ma, et al. ([arXiv:2402.17764](https://arxiv.org/abs/2402.17764)). Clean-room Python implementation with **pure-integer Q16.16 fixed-point arithmetic** — no `torch` runtime dep, no GPU required. Training used PyTorch + Straight-Through Estimator on H200 SXM (RunPod). Diagram source: [`architecture.mmd`](architecture.mmd).
 
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